from json import dump,load
tmp={"name": "汤姆", "city": "火城", "age": 6, "spc": None}

with open('tmp.json','w',encoding='utf8') as f:
    dump(tmp,f,ensure_ascii=False)

with open('tmp.json','r',encoding='utf8') as f:
    d=load(f)
    d['spc']='喷火'
    print(d)

